Wrapping material



Patented Apr. 21,-1936 PATENT OFFICE.

WRAPPING MATERIAL Curt Joseph,Berlin, Germany, assignor to .Syl-

vania Industrial Corporation, Fredericksburg, Va., a corporation of Virginia No Drawing. Application July 14, 1934,-Serial No. 735,287. In Germany April 14, 1931 12 Claims This invention relates to an article of manufacture adapted for the preservation of commodities. More particularly, it relates to an improved wrapping material for protecting lightunstable commodities from the action of ultraviolet light, and includes correlated improvements and discoveries whereby desirable characteristics thereof are enhanced.

It is known that light causes certain undesirable changes in the color, odor, taste, durability and the like of various commodities such as textiles, leather goods, rubber goods, foodstuffs and light-unstable oils, fats and waxes and products containing the same. With regard to the role that light pla'ys in causing undesirable changes in such commodities, the literature is incomplete and full of contradictory statements, in consequence of which many unsatisfactory'types of protective elements have been proposed for re-" tarding such changes in these substances.

All the transparent or semi-transparent wrapping materials which are actually on the market, for example parchment paper, imitation parchment, glassineand other papers, regenerated cellulose sheets, cellulose acetate-sheets,-gelatine sheets and the like, .are limited to a considerable extent as regards applicability in that they allow,

besides the passage of the visible range of the spectrum, the passage of all or part of the ultraviolet light. In the case of dyed articles, such as textile goods, not only the ultra-violet rays, which act chiefly uponthe dyed materials, but also the actual complementary colors of the color to be Y protected exert a very detrimental effect upon the article .to be protected. I

t It is a general object of the invention to provide an improved wrapping material for lightunstable commodities, characterized by shielding such commodities from the action of light capable of promoting undesirable changes in color, odor,

taste, durability and the like, while permitting the transmission of visible light so that the wrapped article may be clearly seen through the wrapper in its natural condition and color. v

It is a further object of the invention to provide, as an improved article of manufacture, a wrapping material for light-unstable oils, fats and waxes and substances containing the same wherebythe development of rancidity in such substances may be substantially retarded while -per-' mitting the use of visible light transmitted by the element for the purposeofdisplaying such substances.for visual examination.

It is a specific object of the invention to provide a novel and improved article of manufacture consisting of a wrapping material characterized 'by being transparent .to and colorless in visible light but substantially opaque to'ultra-violet li ht.

Other objects ofthe invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises a novel article comprising the elements and the relation of elements, all as exemplified in the following detailed disclosure and the scope of the invention will be indicated in the claims.

This invention achieves its objects and pro-.

duces an improved wrapping material not pos- 1 sessing. the disadvantages of the prior materials referred to above by incorporating in a sheet selected from the group consisting of parchment paper, imitation parchment, glassine, regenerated cellulose, cellulose acetate, gelatine', or the like,

' a compound absorbing ultra-violet light, this bee inwhich -W represents a hydroxyl, carboxyl,

amino, alkyl, aryl, or an OR, group in which R represents an alkali metal or an alkyl or aryl group. Suitable 'coumarin derivatives are,- for example, umbelliferone and nuclear substitution products thereof, as carboxyl, hydroxyl or amino derivatives of umbelliferone such as umbelliferone acetic acid and its esters, and the alkalL metal salts such, for example, as sodium and lithium umbelliferonate. Other .coumarin derivatives suitable for use in the invention are p-methyl a-naphthocoumarin, aesculetin, p-methyl oxycoumarin, dimethylamino p-methyl coumarin, chrysaptropic acid, herniarian, p-methyl daphnetine, and p-daphnetine acetic acid. The light-absorbing substances may be used either singly or incompatible admixtures with one another. The concentration of the light-absorbing substances should be sumcient to render the article substantiallyopaque'to that region of ultra-violet light in the solar spectrum which is transmitted by thev atmosphere. Further, the proportions in which the light absorbing substances may be utilized are such as will prodaphnetine,

move ultra-violet rays, causing changes in color, odor and taste. The formulae of certain of the umbelliferone compounds are as follows: Umbel- .liferone sodium C9H5O3Na, umbelliferone acetic acid CHI-I805, and umbelliferone acetic acid ethyl ester C13H12O5.

The particular light-absorbing substance which is selected depends, however, upon the actual.

By way of illustration, but not by way of limit- I ing the scope of the invention, there may be given the following examples of the preparation of an improved wrapping material in accordance with the invention:

Example-1 In a solvent suitable for dissolving cellulose acetate, for example, so much umbelliferone acetic acid ethylester is dissolved'that the end product, after pouring out and drying, produces a sheet which contains 1%o'f the above-mentioned lightabsorbing medium.

- Example 2 To the transparent film structure produced in the ordinary manner from regenerated cellulose a certain. quantity of an ultra-violet absorbing chemical soluble in water is added, before the drying process, for example, in a color bath, so that the finished wrapping material after. the drying contains a suificient quantity of chemicals capable of absorbing ultra-violet light, for example 2%.

Erample 3 A parchment paper capable of absorbing ultraviolet light may be produced .by taking a parchment paper manufactured in accordance with known processes and treating it, either prior to, during, or after the usual drying process, with a solution of a substance capable of absorbing ultra-violet light, as sodium umbelliferone, in a quantity of, for example, about 3%. The paper, when finished by drying, is a parchment which does not differ in any manner in outward appearance from the parchment papers as usually manufactured, but it possesses the property of absorbing ultra-violet light and. certain of the violet rays.

While the above remarks have applied to wrapping materials in which the light-absorbing substance is uniformly distributed and forms an integral' part thereof, the invention also contemplates providing a wrapping material comprising a flexible sheet material which is colorless in and transparent to visible light-and which may be coated with a water-clear lacquer which coating is colorless and contains dissolved therein a small quantity, for instance, 1%3%, of asubstance which renders the coated sheet substantially opaque to ultra-violet light below about 4000 A. U. For example, one may employ a sheet of regenerated cellulose or other suitable material which has been coated with a lacquer comprising a. cellulose derivative, a plasticizer and a gum or resin, to whic has been added 1% of umbelliferone. V

A wrapping material which may be transparent or semi-transparent, that is, translucent, prepared in accordance with the foregoing description is particularly well suited for the wrapping of a considerable variety of articles with respect to which contact with ultra-violet light is deleterious. Thus, butter wrapped in paper in accordance with the invention may be maintained unchanged in odor and taste for marked periods of time. The rancidity or tallowness resulting from oxidation produced by ultra-violet light in the presence of oxygen is prevented by the absorption of the ultra-violet rays by the wrapping material, resulting in a maintenance of the characteristic freshness of the butter. The wrapping material may be utilized for the wrapping of many other products, as meat, salads, mayonnaise, margarine, fats, baked products, tea, chocolate, coffee, fish, sausages, fruits preserves in glass containers, vegetables, soaps, leather goods, rubber goods, textiles, etc.

It will be observed also that goods packed using the wrapping material of the invention are protected on all sides, not only from ultra-violet light but'from other undesirable action, such as the accumulation of dust, absorption of odors, etc. Hence, goods so wrapped are not limited to a par ticular place of storage. Further, the use of a transparent or translucent wrapping material renders the goods so wrapped visible so that the prospective customer is able to see thenatural condition and color. It will be understood that the term transparent as used in the claims connotes a translucent as well as a water-clear transparent material.

Furthermore, it may be added that substances which possess thev property of absorbing ultraviolet light are widely difierent in the extent to which such absorption is effected. The inven tion contemplates the use of substances which .are highly absorbent, and hence with respect to which it is necessary to incorporate only a small percentage, in order to effect a substantially complete absorption of ultra-violet rays which cause changes in color, odor and taste. The power of non-glucosidic derivatives of coumarin to absorb ultra-violet rays is so marked that an amount may readily be combined with a flexible sheet of material so as to render the sheet opaque .to ultraviolet light but without any crystallization of the added derivative. This is not the case with other recognized ultra-violet light absorbing substances when an equal degree of absorption is to be obtained. Thus, aesculin, quinine compounds and others, while having the property of absorbing ultra-violet light, nevertheless, even when utilized in an amount such that salts crystallize upon the sheet, are far from giving such opacity as results from the use of non-glucosidic coumarin derivatives. This may be demonstrated through the use of a photoelectric eye which. by means of a suitable filter, is operable only by ultra-violet light. When such an eye or cell is connected The advantages arising fromthe use of the.

non-glucosidic derivatives of coumarin as contemplated by applicant in his invention will, accordingly, be apparent and this especially so in view of the fact that, while the amounts used are suflicient to exclu'dethe ultra-violet rays occasioning changes in color, taste and odor, nevertheless the appearance and transparency of the sheet are not affected.

This application is in part a continuation of my co-pending application Serial No. 604,885, filed April 12, 1932.

Since certain changes may be made in the above article and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter con-' tained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. As an article of manufacture, a wrapping material comprising a flexible sheet of transparent non-fibrous material combined with a nonglucosidic coumarin derivative, said article being transparent to visible light and substantially opaque to ultra-violet light, and said coumarin derivative being present in proportions sufiicient to remove ultraviolet rays causing changes in color, odor and taste without detracting from the transparency of the sheet material.

2. As an article of manufacture, a wrapping material comprising a flexible sheet of colorless, transparent, non-fibrous cellulosic material combined with a non-glucosidic coumarin derivative, said article being colorless in visible light and substantially opaque to ultra-violet light, and said coumarin derivative being present in proportions sufficient to remove ultra-violet rays causing changes in color, odor and taste, without detracting from the transparency of the sheet material.

3. As an article of manufacture, a wrapping material comprising a flexible sheet of colorless, transparent, non-fibrous material combined with a non-glucosidic coumarin derivative in an amount of from 1% to 3%, said article being colorless in visible light and substantially opaque to ultra-violet light.

4. As an article of manufacture a wrapping material comprising a flexible sheet of colorless, transparent regenerated cellulose combined with a non-glucosidic coumarin derivative, said article being colorless in visible light and substantially opaque to ultra-violet light, and said coumarin derivative being present in proportions sufficient to remove ultra-violet rays causing changes in color, odor and taste, without detracting from the transparency of the sheet material.

5. As an article of manufacture, a wrapping material comprising a flexible sheet of colorless transparent cellulose acetate combined with a non-glucosidic coumarin derivative, said article being colorless in visible light and substantially opaque to ultra-violet light-said coumarin derivative being present in proportions suflicient to remove ultra-violet rays causing changes in color, odor and taste without detracting from the transparency.

6. As an article of manufacture, a wrapping material comprising a flexible sheet of transparent non-fibrous material combined with an umbellifero'ne compound, said article being transparent to visible light and substantially opaque to ultra-violet light, said umbelliferone compound being present in proportions sufiicient to remove tracting from the transparency of the sheet material.

8. As an article of manufacture, a wrapping material comprising a flexible sheet of colorless, transparent regenerated cellulose combined with an umbelliferone compound, said article being colorless invisible light and substantially opaque to ultra-violet light, said umbelliferone compound being present in proportions sufficient to remove ultra-violet rays causing changes in color, odor and taste, without detracting from the transparency of the sheet material.

9. As an article of manufacture, a wrapping material comprising a flexible sheet of transparent parchment paper combined with an umbelliferone compound, said article being transparent to visible light and substantially opaque to ultra-violet light, said umbelliferone compound being present in proportions to produce a colorless sheet and sufiicient to remove ultra-violet rays causing changes in color, odor/ and taste without detracting from the transparency of the sheet material.

10. As an articleof manufacture, a wrapping material comprising a flexible sheet of colorless, transparent non-fibrous material combined with an umbelliferone acetic acid compound, said article being colorless in visible light and substantially opaque to ultra-violet light, said umbelliferone acetic acid compound being present in proportions sufficient to remove ultra-violet rays causing changes in color, odorand taste, without detracting from the transparency of the sheet material.

11. As an article of manufacture, a wrapping materlalkcomprising a flexible sheet of colorless, transparent regenerated cellulose combined with umbelliferone acetic acid ethyl ester, said article being colorless in visible light and substantially opaque to lightof wave lengths shorter than 4000 A. U., and said sheet having an ester content of from 1 to 3%.

12. As an article of manufacture, a wrapping material comprising a flexible sheet of transparent material selected from the group consisting of parchment paper, glassine, regenerated cellulose, cellulose acetate, gelatine, combined with a, non-glucosidic coumarin derivative, said article being transparent to visible light and substantially opaque to ultra-violet light, and said coumarin derivative being present in proportions suflicient to remove ultra-violet rays causing changes in color, odor and taste without detracting from the transparency of the sheet material.

CURT JOEPH. 

